Country-specific modifiable dementia risk factors across the Western Pacific Region determined by population attributable fraction.

Abstract

One-third of global dementia cases occur in the Western Pacific Region (WPR), a region of marked socioeconomic and cultural diversity. Understanding how modifiable risk factors contribute to dementia burden across countries is essential for designing context-specific prevention strategies. This study quantified country-level variability in dementia cases attributable to modifiable risk factors across the WPR. Weighted population attributable fractions (PAFs) for nine modifiable factors: low education, obesity, physical inactivity, hypertension, diabetes, smoking, hearing loss, depression, and alcohol misuse were calculated for 32 countries. For 13 countries with full datasets, combined weighted PAFs were also generated for seven of the nine factors (excluding hearing loss and alcohol misuse). PAF values were compared across high-, upper-middle-, and lower-middle-income countries to explore socioeconomic patterns. Weighted PAFs showed substantial cross-country variability. The largest variation occurred for low education (0.0-7.3%; n = 16; vs global 4.5%) and obesity (0.2-5.9%; n = 28; vs global 1.4%). Hypertension (0.9-2.2%; n = 27; vs global 2.2%) and alcohol misuse (0.0-0.5%; n = 24; vs global 1.0%) showed the least variation. Combined weighted PAFs ranged from 20.1% (Singapore) to 34.7% (Papua New Guinea). Income-related patterns emerged: low education contributed most to dementia burden in lower-middle-income countries, while diabetes and depression contributed more in upper-middle- and high-income countries. Eliminating seven modifiable risk factors could prevent 20-35% of dementia cases across the WPR. Region-wide gains may be achieved by focussing on diabetes and hearing loss, while effective prevention strategies require tailoring to country-specific socioeconomic conditions, health-system capacity, and education inequalities. This work was made possible through Dementia Australia's support of their Chair of Dementia (author BCMS). KJA is funded by an Australian Laureate Fellowship - Grant ID: FL190100011.